Richer nations at more risk of schizophrenia

Schizophrenia is more common in developed countries than poorer nations, but it is less widespread than previously thought.

These findings are from a Queensland Centre for Mental Health Research (QCMHR) report, published in the American-based journal Public Library of Science Medicine.

The report debunks a popular textbook definition that schizophrenia will affect 10 in every 1000 people no matter where patients live.

It says this rate is too high and more likely, between seven and eight in 1000 people, although this varied between sites.

Poorer countries also had more women with the illness than men.

The University of Queensland’s Professor John McGrath, who led the research team, said the 21-page-report was the biggest and most comprehensive survey of schizophrenia rates around the globe.

His team collected 188 schizophrenia studies dating from 1965 to 2002 from 46 countries.

The group was funded by Queensland Health and US-based private health foundation the Stanley Medical Research Institute.

Professor McGrath, a UQ Professor of Psychiatry and QCMHR’s Director of Epidemiology said the study would help health care planners see the bigger picture for the illness.

“Health budgets look at ‘dollar per disability avoided. . . Health care planners need to know prevalence rates in order to allocate staff and funds,” Professor McGrath said.

Schizophrenia is a group of brain disorders with symptoms such as hallucinations, delusions, disorganised communication, poor planning and reduced motivation.

Professor McGrath said he believed schizophrenia varied from region to region.

“Our data shows that the incidence and prevalence of schizophrenia varies much more around the world than previously acknowledged.

“My hunch is that the subtypes of schizophrenia vary between countries.

“Maybe the mix of illnesses we see here in Australia are different to the mix they get in Mumbai or Zambia or Tokyo.”

He said to explain the results his team would try to match up new cases with current case data from the same sites and same times to help answer prognosis and illness duration questions.

The report is a companion to an earlier study by the same team on the number of new cases of schizophrenia worldwide.

It revealed that schizophrenia affected more men than women, more migrants than native-born citizens and was more common in cities than urban/rural areas.

Mass Extinctions without Astrophysical Calamities

Mass extinctions seem to occur on Earth roughly every 26 million years, leading some scientists to propose that they may be caused by rare collisions with comets or asteroids. A researcher in Poland thinks it may be possible that extraordinary predators are at fault instead.

Adam Lipowski (Adam Mickiewicz University) constructed a numerical model of many species competing for both food and living space. The model also included a term that controls mutation rates, allowing new species to develop over time. The model shows that, much of time, the system is populated with “medium efficiency” predators whose numbers fluctuate only slightly as the prey population waxes and wanes. Inevitably, their stable community is disrupted when mutations lead to a super predator that quickly decimates the prey population, which in turn leads to its own demise. The few creatures that survive the predatory apocalypse gradually mutate to fill the existing ecological niches – and the cycle begins again.

The period of the cycle depends on mutation rates in the model. The lower the mutation rate, the longer the periods between super predators. For a sufficiently low mutation rate, the model can lead to cycles that correspond to our 26 million year mass extinctions.

Previous models that do not show these sorts of cycles could be faulty, according to Lipowski, because they failed to account for the effects of limited living spaces shared by a large number of different species.

A. Lipowski
Phys. Rev. E 71, 052902 (2005), 20 May 2005
http://link.aps.org/abstract/PRE/v71/e052902

Music Tickles Strong Memories

If the song “It’s a Small World” has ever driven you bananas, then you’ve got an idea where this story is going.
We’ve all had tunes stuck in our heads. Some of them remind us of childhood friends, places or events.
A new study backs the obvious notion that a song can evoke strong memories. It also reveals that you don’t even have to hear a song for the past to come flooding back.
In fact, most people have an amazing ability to effectively hear songs that aren’t even being played.”

Link

Business 2.0: B2 100: Best Investments

“These eight tech companies are big (with revenues greater than $1.3 billion), fast-growing (they rank on our list of the 100 fastest-growing technology companies this year), and posted an impressive stock return last year — greater than 25% for the 12 months ending March 31, 2005. “

Link

Experts: Petroleum May Be Nearing Peak

“Could the petroleum joyride ‚Äî cheap, abundant oil that has sent the global economy whizzing along with the pedal to the metal and the AC blasting for decades ‚Äî be coming to an end? Some observers of the oil industry think so. They predict that this year, maybe next ‚Äî almost certainly by the end of the decade ‚Äî the world’s oil production, having grown exuberantly for more than a century, will peak and begin to decline.
And then it really will be all downhill. The price of oil will increase drastically. Major oil-consuming countries will experience crippling inflation, unemployment and economic instability. Princeton University geologist Kenneth S. Deffeyes predicts “a permanent state of oil shortage.””

– Yahoo! News (http://news.yahoo.com/news?tmpl=story&cid=1894&e=1&u=/ap/20050529/ap_on_bi_ge/oil_gone)

Engineers Design Tsunami-Resistant Homes

“CAMBRIDGE, Mass. (AP) _ Not long after the devastating December tsunami, a team of structural engineers from London visited Sri Lanka and noticed a trend as they surveyed destroyed homes: Walls facing the sea were leveled, while those perpendicular to it were standing.
That inspired a group of researchers from the Massachusetts Institute of Technology and Harvard University to design what they’re calling a “tsunami-safe(r) house” that is less likely to collapse under wind and pounding surf.
Instead of having four solid walls, the tsunami-resistant houses have thick concrete-block corners and exterior walls made of bamboo. The houses, about 80 of which have already been built, are designed to be built on top of blocks of concrete or wood, one or two feet above the ground.”

(http://www.livescience.com/technology/ap_050527_tsunami_house.html)

'Gender-bending' chemicals found to 'feminise' boys

Gender-bending chemicals mimicking the female hormone oestrogen can disrupt the development of baby boys, suggests the first evidence linking certain chemicals in everyday plastics to effects in humans.

The chemicals implicated are phthalates, which make plastics more pliable in many cosmetics, toys, baby-feeding bottles and paints and can leak into water and food.

All previous studies suggesting these chemicals blunt the influence of the male hormone testosterone on healthy development of males have been in animals. This research highlights the need for tougher controls of gender-bending chemicals, says Gwynne Lyons, toxics adviser to the WWF, UK. Otherwise, wildlife and baby boys will be the losers.
(http://www.newscientist.com/article.ns?id=dn7440&feedId=online-news_rss20)

Violence may be a 'socially infectious disease'

There is evidence that actually winessing violence can raise the probability that the individual will be more violent.

Witnessing gun violence can double the likelihood of a teenager committing serious violence in the following two years, suggests a new study by US researchers.

Although a connection between exposure to violence and violent behaviour has been previously suggested, it is difficult to show a direct causal link. But this study claims to have isolated the independent contribution made by actually witnessing gun violence by comparing over 1500 teenagers with a similar likelihood of being exposed to violence.

Based on this studys results, showing the importance of personal contact with violence, the best model for violence may be that of a socially infectious disease, says Felton Earls, at Harvard Medical School, US, who led the study. Preventing one violent crime may prevent a downstream cascade of infections.

Personal contact with violence raises the probability that the individual will be “infected” with it.

The children and their parents or primary carers were interviewed on three occasions over a five-year period. In the two years after witnessing gun violence, “the exposure group were two to three times more likely to engage in violent behaviour themselves”, he says.

“When individuals have such traumatic experiences – witnessing or being exposed to gun violence – it makes them hyper-vigilant,” says Daniel Webster, co-director of the Center for Gun Policy and Research at the Johns Hopkins Bloomberg School of Public Health in Baltimore, US.

“There are often social stimuli that are ambiguous – like at a crowded party, someone bumps into you. How do you interpret those stimuli?‚Äù he asks. Webster suggests that people exposed to violence may be more prone to assume a hostile intent – as a self-defence mechanism – which could in itself lead to violence.

More study is needed concerning the difference between “fake” violence in movies and games and real violence. Does the sub-concious differentiate between the two so that only real violence impacts the individual?

(http://www.newscientist.com/article.ns?id=dn7436&feedId=online-news_rss20)

Physicists control the flip of electron spin in new study

Physicists control the flip of electron spin in new study
ATHENS, Ohio Today’s computers and other technological gizmos operate on electronic charges, but researchers predict that a new generation of smaller, faster, more efficient devices could be developed based on another scientific concept electronic “spin.” The problem, however, is that researchers have found it challenging to control or predict spin which keeps practical applications out of reach.
But physicists in Europe, California and at Ohio University now have found a way to manipulate the spin of an electron with a jolt of voltage from a battery, according to research findings published in the recent issue of the journal Physical Review Letters.

In the new study, scientists applied voltage to the electron in a quantum dot, which is a tiny, nanometer-sized semiconductor. The burst of power changed the direction of the electron’s spin — which can move either up or down. This also caused it to emit a small particle of light called a photon, explained Richard Warburton, a physicist with Heriot-Watt University in Edinburgh, Scotland, and lead author on the new paper.

“Usually you have no control over this at all an electron flips its spin at some point, and you scratch your head and wonder why it happened. But in our experiment, we can choose how long this process takes,” he said.

The experiment was based on a theory by Sasha Govorov, an Ohio University associate professor of physics and astronomy who is co-author on the current paper. Pierre Petroff, a scientist with the University of California at Santa Barbara, contributed the semiconductor used in the experiment, Indium Arsenide, which commonly is used in electronics. “It’s one of those happy collaborations — Pierre has given us some fantastic material and Sasha has come up with some really smart ideas,” Warburton said.

The scientists were able to manipulate how long it would take for the electron to flip its spin and emit a photon from one to 20 nanoseconds. But Govorov’s theory suggests that 20 nanoseconds isn’t the upper limit, which will lead the physicists to try out longer time periods.

Scientists’ abilities to control the spin of the electron help determine the properties of the photon, which in turn could have implications for the development of optoelectronics and quantum cryptography. Photons could be encoded with secure information, which could serve as the basis for anti-eavesdropping technology, Warburton said.

The current study is one of many in the growing field of nanoscience that aims to find, understand and control physical effects at the nanoscale that could serve as the basis of a new generation of technology that is smaller and more powerful than today’s electronic devices, Govorov said.

“The principles, knowledge and experience will be used for practical, real devices, we hope,” he said.

The study was funded by EPSRC in the United Kingdom, Ohio University, Volkswagen, and the Alexander von Humboldt Foundations, with additional support by the Scottish Executive and the Royal Society of Edinburgh. Collaborators on the paper are Jason Smith and Paul Dalgarno of Heriot-Watt University, Khaled Karrai of the Ludwig-Maximilians-Universitat in Germany, and Brian Gerardot and Pierre Petroff with the University of California Santa Barbara.

Nanoscale light tricks promise huge DVD storage

“The tantalising prospect of DVDs capable of holding almost a terabyte of data – or several hundred movies – has been presented in a patent issued to US storage company Iomega.
The US patent describes a disc that could store 40 to 100 times more information that a conventional DVD, using more nanometre-scale sloped ridges to diffract light. US patent number 6879556 – entitled “Method and Apparatus for Optical Data Storage” – was issued to Iomega on April 12 2005.”

(http://www.newscientist.com/article.ns?id=dn7432&feedId=online-news_rss20)